//回文子串
//测试链接：https://leetcode.cn/problems/palindromic-substrings/
public class CountSubstrings {
    public int countSubstrings(String s) {
        int n = s.length();
        boolean[][] dp = new boolean[n][n];
        int ret = 0;
        for (int i = n - 1; i >= 0; i--) {
            for (int j = i; j < n; j++) {
                if (s.charAt(i) == s.charAt(j))
                    dp[i][j] = i + 1 < j ? dp[i + 1][j - 1] : true;
                if (dp[i][j])
                    ret++;
            }
        }
        return ret;
    }
}
